A633 Gr.A/C/D SMAW (low-hydrogen) 예열 — up to 3/4"

SMAW (Low-Hydrogen)

Low-hydrogen SMAW (E7018/E7016) uses basic-coated electrodes requiring rod oven storage, assigned to Category B in Table 5.11.

On pressure vessel plate, E7018 is the standard manual electrode for nozzle welds, manhole reinforcements, and repair welding. ASME Section IX procedure qualifications typically require all-weld-metal tensile and guided bend tests. Rod moisture control is critical in vessel fabrication because vessel codes impose stricter hydrogen limits than structural codes.

A633 Gr.A/C/D

ASTM A633 Grades A, C, and D are normalized high-strength low-alloy structural plates with enhanced notch toughness for structural applications at temperatures down to -75°F. Grade A (42 ksi yield) provides basic low-temperature service; Grade C (50 ksi yield) is the most widely specified for cold-region bridges; Grade D (50 ksi yield) offers the lowest test temperature at -75°F for Arctic service. All are normalized to produce a fine-grained microstructure that resists brittle fracture. They fall under Category B in Table 5.11, with chemistry limits (0.20% max carbon for Gr.C/D, Nb and V microalloying) producing a CE-IIW of 0.38-0.44. Charpy V-notch specimens are tested in the transverse direction at -50°F (Gr.C) or -75°F (Gr.D) with 20 ft-lbs minimum absorbed energy per ASTM requirements.

SMAW-LH를 사용한 A633 Gr.A/C/D의 이 예열 이유

Normalized HSLA plate with enhanced toughness for cold environments to -75°F. This steel is prequalified only with low-hydrogen processes under Table 5.11, which is why it appears in Category B but not Category A. The 32°F minimum preheat with SMAW-LH balances the steel's strength level and carbon equivalent against the controlled hydrogen input from the consumable. Non-low-hydrogen SMAW is not an option for this grade under D1.1 prequalified WPS.

A633 Gr.A/C/D의 일반적인 용도

Specified for bridge pier caps in cold regions, offshore platform deck plates, Arctic pipeline support structures, cold-climate building trusses, icebreaker hull stiffeners, and polar research station framing. A633 Grades C and D provide guaranteed Charpy toughness at -40°F and -75°F respectively, making them essential for structures operating in extreme cold where brittle fracture is the primary failure mode. Impact specimen orientation (longitudinal vs transverse) affects the guaranteed toughness values and must be specified at procurement. Field welding on A633 in sub-zero ambient conditions requires heated enclosures or windbreaks to maintain interpass temperature above the Table 5.11 minimum. Filler metals for cold-region service must also meet CVN requirements at the design service temperature, typically requiring -20°F or colder impact testing. Weld procedure qualification includes impact testing of the weld metal and HAZ at the minimum design temperature.

up to 3/4"에서 예열이 중요한 이유

Thin material sheds heat quickly, allowing hydrogen to escape the HAZ readily — lowest preheat tier in Table 5.11.

up to 3/4"에서 SMAW (low-hydrogen)를 사용하는 다른 강재

A633 Gr.A/C/D, SMAW (low-hydrogen)

다양한 조합 시도

인터랙티브 예열 계산기를 사용하여 D1.1:2025 표 5.11의 모든 강재, 공정, 두께 조합을 조회하세요.

A633 Gr.A/C/D 용접 가이드